From b84518625183e87c6930b11db0592be786181128 Mon Sep 17 00:00:00 2001 From: Roland Stigge Date: Wed, 8 Feb 2012 21:41:05 +0100 Subject: [PATCH] ARM: LPC32xx: clock.c: Fix mutex lock issues This patch fixes the mutex issue in clock.c, as done in Kevin Wells' original driver update: In some cases, the clock drivers could grab a mutex twice in an improper context. This patch changes the mutex mechanism to a simple irq lock/unlock mechanism and removes un-needed locks from some functions. (See also git.lpclinux.com) Signed-off-by: Roland Stigge Tested-by: Wolfram Sang Acked-by: Kevin Wells Signed-off-by: Olof Johansson --- arch/arm/mach-lpc32xx/clock.c | 41 ++++++++++------------------------- 1 file changed, 11 insertions(+), 30 deletions(-) diff --git a/arch/arm/mach-lpc32xx/clock.c b/arch/arm/mach-lpc32xx/clock.c index 39dcbd0e68b2..fef863062a5e 100644 --- a/arch/arm/mach-lpc32xx/clock.c +++ b/arch/arm/mach-lpc32xx/clock.c @@ -97,9 +97,10 @@ #include "clock.h" #include "common.h" +static DEFINE_SPINLOCK(global_clkregs_lock); + static struct clk clk_armpll; static struct clk clk_usbpll; -static DEFINE_MUTEX(clkm_lock); /* * Post divider values for PLLs based on selected register value @@ -891,16 +892,6 @@ static struct clk clk_lcd = { .enable_mask = LPC32XX_CLKPWR_LCDCTRL_CLK_EN, }; -static inline void clk_lock(void) -{ - mutex_lock(&clkm_lock); -} - -static inline void clk_unlock(void) -{ - mutex_unlock(&clkm_lock); -} - static void local_clk_disable(struct clk *clk) { /* Don't attempt to disable clock if it has no users */ @@ -945,10 +936,11 @@ static int local_clk_enable(struct clk *clk) int clk_enable(struct clk *clk) { int ret; + unsigned long flags; - clk_lock(); + spin_lock_irqsave(&global_clkregs_lock, flags); ret = local_clk_enable(clk); - clk_unlock(); + spin_unlock_irqrestore(&global_clkregs_lock, flags); return ret; } @@ -959,9 +951,11 @@ EXPORT_SYMBOL(clk_enable); */ void clk_disable(struct clk *clk) { - clk_lock(); + unsigned long flags; + + spin_lock_irqsave(&global_clkregs_lock, flags); local_clk_disable(clk); - clk_unlock(); + spin_unlock_irqrestore(&global_clkregs_lock, flags); } EXPORT_SYMBOL(clk_disable); @@ -970,13 +964,7 @@ EXPORT_SYMBOL(clk_disable); */ unsigned long clk_get_rate(struct clk *clk) { - unsigned long rate; - - clk_lock(); - rate = clk->get_rate(clk); - clk_unlock(); - - return rate; + return clk->get_rate(clk); } EXPORT_SYMBOL(clk_get_rate); @@ -992,11 +980,8 @@ int clk_set_rate(struct clk *clk, unsigned long rate) * the actual rate set as part of the peripheral dividers * instead of high level clock control */ - if (clk->set_rate) { - clk_lock(); + if (clk->set_rate) ret = clk->set_rate(clk, rate); - clk_unlock(); - } return ret; } @@ -1007,15 +992,11 @@ EXPORT_SYMBOL(clk_set_rate); */ long clk_round_rate(struct clk *clk, unsigned long rate) { - clk_lock(); - if (clk->round_rate) rate = clk->round_rate(clk, rate); else rate = clk->get_rate(clk); - clk_unlock(); - return rate; } EXPORT_SYMBOL(clk_round_rate);